I see the discussion in the
https://www.alternatehistory.com/fo...ubishi-zero-won-the-battle-of-britain.461199/
seems to derail to the German-Japanese cooperation topic, and therefore create a more focused thread.
Possibly questions need to be clarified:
1) How much OTL cooperation obstacles (large distance, lack of common goal, and lack of trust) can be overcome in ATL scenarios?
2) Is any hybrid German/Japanese WWII design with significant impact (similar or better than widely known Sherman Firefly)?
3) How much difference, in both peace and war, such cooperation can bring?
Some possibilities:
1) Raw materials exchange - for example, Japan had abundant nickel-manganese deposits but not enough chromium, with situation reverse in Germany - due access to Yugoslavian and Albanian chromium ores. IOTL, exchange was more limited to lower-volume materials (for example, German mercury swapped for Japanese caffeine and natural rubber).
2) Technological exchange - for example,Japanese super-duralumin (A7075) alloy tech for German equipment or blueprints (Japan had problems with screw making machines as late as in 1940)
3) Basing rights, may be with additional cooperating states within reach of both Japan and Germany (Axis Soviet Union, independent Iran or Axis Madagascar options)
4) Anything else?